1. Field of the Invention.
The present invention is directed to a swaging process and apparatus to produce efficient terminations in wire rope. In particular, the present invention is directed to a method involving a swaging process and apparatus for use in the method to convert a cylindrical swaging sleeve surrounding a wire rope into a sleeve having a non-circular external cross-sectional shape. In a particular application, the method of this invention is useful in attaching swage socket type termination elements to the end portion of a wire rope. Such swage socket terminations are typically either an open swage socket wherein the termination element has spaced apart parallel integral tang portions or the swage socket is a closed swage socket in which the termination element has a body portion with an opening through it.
2. Prior Art.
Wire rope termination fittings generally comprise cylindrical swaging sleeves that are used in a variety of wire rope terminations. Typically, swaging sleeves are externally and internally cylindrical and sized to receive therein a particular size of wire rope. A sleeve typically used to form a wire rope sling eye, particularly of the Flemish-eye splice form of termination, is cylindrical with one end being tapered, such sleeves form the termination by swaging, i.e., cold forming the sleeve to form a strong union with the wire rope. Such swages and methods for forming them are known in the prior art and described in the NATIONAL SWAGE CATALOG of The Crosby Group, Inc.
In the prior swage forming processes, a round sleeve is positioned at the termination point and then placed within open co-acting cylindrical dies. The shape of the cylindrical die represents the size of the finished swage for a given size of wire rope identified as the "after swage dimension". The prior art process requires that the co-acting dies are closed partially to approximately one-half the distance from the time initial contact is made between the sleeves and the dies. The die is then opened and the sleeve is rotated. This step is repeated upwards of 3 to 4 times until the dies actually close and abut to create the after swage dimension sufficient to sustain the working load limits for a given wire rope size. As the size of the wire rope increases even more repeated turning of the sleeve and multiple pressing is required.
One pass swaging has been taught in the prior art such as U.S. Pat. No. 2,151,032; British Patent 1,249,352, dated Oct. 13, 1971; and PCT/GB94/02025 filed Sep. 16, 1994. Such a method and apparatus will create unwanted "flash" of swage material between the die "land" surfaces if the dies are closed too much during the first and second swaging passes.